The purpose of the proposed training program is to prepare highly qualified men and women for creative careers in basic cancer research. As in the past, a primary emphasis of the program is research training in the molecular genetics of fundamental cellular processes relevant to understanding the etiology of cancer and ultimately developing improved methods for diagnosis and treatment. The faculty of the Program are members of the Department of Molecular Biology and Genetics at the Johns Hopkins University School of Medicine. The research interests represented among the faculty include: the replication of the genomes of tumor viruses and cells, the regulation of cellular proliferation by growth factors and oncogenes, the control of the mammalian cell cycle, the structure and function of chromosomes, the regulation of gene expression in normal and neoplastic growth, the molecular genetics of retrotransposons, the mechanisms of cellular signal transduction, and the functions of growth and differentiation factors in development and carcinogenesis. Five of the fourteen faculty of the Training Program are members of an NCI-supported program project grant, now in its twenty-fifth year, that is focused on basic cellular mechanisms that control cell growth and maintain genomic stability. Three additional members received direct support from the ACS or other private cancer funding agencies during the past grant period, while the cancer-related work of the remaining faculty is supported by other agencies (NIH and HHMI). Both predoctoral (7) and postdoctoral (4) trainees are supported under this training grant. Predoctoral trainees must have a strong background and o u t standing undergraduate accomplishment in quantitative science, and preferably some background in modern biology including genetics. They must first be accepted into the interdepartmental Graduate Program in Biochemistry, Cellular and Molecular Biology at the Johns Hopkins University School of Medicine and must satisfactorily complete the first year course and laboratory rotations of that program. At the end of the first year students are selected for admission into the Program in Molecular Genetics of Tumor Viruses and Cells at an average rate of about two per year with a steady state number of seven. The remainder of their training consists of laboratory research designed to encourage creativity and self-reliance, required elective courses related to basic cancer research, practical instruction in the techniques of modern molecular genetics, and active participation in research seminars and journal clubs. Postdoctoral trainees must have completed the requirements for the Ph.D. or M.D. and must have outstanding accomplishment and potential for creative careers in cancer-related research at a basic or clinical level. They spend almost all of their time carrying out an individual research project under the close supervision of a faculty member participating in the program. They also participate actively in research seminars and journal clubs involving the entire program personnel and, as appropriate, take formal courses related to cancer biology offered within the University. The Program has a long record of success in recruiting and training outstanding basic investigators. The majority of our students and postdoctoral trainees go on to careers in basic research relevant to cancer at high quality academic institutions or pharmaceutical/biotechnology organizations.